Back in '79/'80/'81 the Porsche entered 924 turbo ran several iterations of the turbo including a crude top mounted IC for the Monte Carlo rallies. They also ran the CGT spec motor/chassis in a 924 turbo body. The CGT and GTS upgrades are all listed in the homologation papers which can be found online. I can't find a link right now. Some of those upgrades should be allowable in group 4.

There is a casting number on the hotside of the turbo which is hard to see when fitted to the motor which would tell you if you have a #4 or #6 hotside. Knowing which compressor is fitted is harder unless pulled apart. I wouldn't worry too much now.

Mittelmotor are running a CGT with all GTS upgrades in FIA Historique racing. Whilst this is track and not rally, there will be upgrades that can be allowed depending on aiming for group 3 or 4 spec. They run higher boost and a 123ignition based programmable distributor to get their car close to 400bhp! This is with additional GTS spec fueling and IC. The turbo, CGT and GTS spec cars did rally with Jurgen Barth at the wheel.

My car is running their dizzy, a 944 front mounted IC and manual boost controller with many other upgrades pushing power over CGT bhp. But as mentioned, an AFR, boost and potentially a knock sensor would be advisable if the car is going to be worked hard

So, I think consensus is to get the car running well first whilst learning and doing some homework on allowable/desirable upgrades. Some may be scrutineered harder than others. Some may be easy to apply and not found. Some may be outside the 'spirit of competition'.

Again: many thanks for useful comments and tips.
As for Homologation, it is probably not that big a deal. These cars don't get scrutinised that often, but I would like to keep it close to the specs. Realy interesting about the GTS homologation info.

I have ordered some service parts and pulled the brakes. Will hone the calipers and install fresh rubber as soon as it arrives.

OT:
While waiting for Porsche parts I have started to put together my other racer. An MG Midget which I have raced in historic Racing (track). I have had the car for 20+ years but have now done some major TLC including machine turning the door sides with a hand drill!
_________________Knut
931 RMCH

Front calipers are now honed and with fresh rubber.
New tiiming belt and roller
New oil an oil filter
Degreased the engine and front crossmember for 20 years of gunk.
cleaned the sparkplugs (too nice to discard)
Running currently without airfilter, since I havent sourced this part yet. Will get a K&N or Pipercross one.

So: Car starts realy easy, and ideling is smooth and steady. But as soon as I try to rev it it feels like 3 cylinders.
Something might be off on the timing. Will check that later.
If anyone has any suggestions, they are more than welcome

Have final had the time to put the car on the lift to have a proper look at the car. i have also been able too get bits of the history of the car.

The good news is that the car had a major engine overhaul with all new bearings, pistons, rings ++. In addition, the injectors have been syncronized. This was about 20.000km ago, and some of the parts was actual bought through this website on a groupbuy in 2009.

Further good news is that there is no rust holes or other rust damage. There is however, substantial surface rust everywhere, so the car must be taken apart and properly refurbished.

I won’t have time to start this project now, but might start during the summer.

Here are som pics to tell the story so far:

Car final on the lift.

Interior is all good, with rally computer and hydraulic hand brake:

Hydraulic handbrake is feed directly into the brake line:

Some rust repair have been done to the floor:

Small oil leak from turbo:

Bigger oil leak from this area:

Welded fixing point for skid pan:

Rear fixing point for the skid pan is same as the A-arms! Not sure, this is the best idea, but the car has done 4 Rally Monte Carlo runs with this setup. I will probably weld in a bracket at a later date.

Floor looks to be in good condition

Someone tried to remove the vinyl wrap without heating it up. They took away the paint as well…

I had an old roof rack laying around. Small mod and it will fit perfectly.
_________________Knut
931 RMCH